c语言内存池分配

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118

#include <iostream> using namespace std; #include <stdlib.h> #include <stdio.h> #include <stdio.h> #include <memory.h> #include <malloc.h>   struct _page {     struct _page* next;     char begin[0]; }; struct _huge_page {     struct _huge_page* next;     size_t size;     char begin[0]; }; struct mpool {     struct _page* pages;     size_t npage;     size_t size;     size_t used;     size_t nalloc;     struct _huge_page* huges;     size_t nhuge; }; struct mpool* mpool_new(size_t page_size) {     size_t cap = 1024;     while (cap < page_size)         cap *= 2;     struct mpool* m = (struct mpool*)(malloc(sizeof(*m)));     struct _page* p =  (struct _page*)(malloc(sizeof(*p) + cap));     p->next = NULL;     m->pages = p;     m->npage = 1;     m->size = cap;     m->used = 0;     m->nalloc = 0;     m->nhuge = 0;     return m; } void mpool_delete(struct mpool* m) {     if (m) {         struct _page* p;         while (m->pages) {             p = m->pages;             m->pages = p->next;             free(p);         }         struct _huge_page* hp;         while (m->huges) {             hp = m->huges;             m->huges = hp->next;             free(hp);         }         free(m);     } }   void* mpool_alloc(struct mpool* m, size_t n) {     n = (n+3) & ~3;     if (n >= m->size) {         struct _huge_page* p =(struct _huge_page*)(malloc(sizeof(*p) + n));         p->size = n;         p->next = m->huges;         m->huges = p;         m->nhuge += 1;         m->nalloc += n;         return p->begin;     }     if (m->used + n > m->size) {         struct _page* p = (struct _page*)(malloc(sizeof(*p) + m->size));         p->next = m->pages;         m->pages = p;         m->npage += 1;         m->used = 0;         m->nalloc += n;         return p->begin;     } else {         void* ptr = m->pages->begin + m->used;         m->used += n;         m->nalloc += n;         return ptr;     } }   void* mpool_realloc(struct mpool* m, void* p, size_t n) {     return mpool_alloc(m, n); }   void mpool_dump(struct mpool* m) {     printf("[npage:%zu] ", m->npage);     printf("[total pagesize:%zu] ", m->npage*m->size);            printf("[nhuge:%zu] ", m->nhuge);     size_t n = 0;     struct _huge_page* h = m->huges;     while (h) {         n += h->size;         h = h->next;     }     printf("[total huge size:%zu] ", n);       printf("[nalloc:%zu]\n", m->nalloc); }   int main() {    struct mpool* m;   cout<<sizeof(*m)<<endl;      return 0; }